The Unpermitted Dams Initiative in Washington State

This paper discusses an initiative by Washington State’s dam safety program to find, inspect and eventually bring into compliance dams that had been constructed without prior approval by the state. The Dam Safety Office of the Washington State Department of Ecology has jurisdiction over any dam that can impound 10 or more acre-feet of water at the dam crest. In March 2008, the Dam Safety Office (DSO) started the effort to find dams that meet this threshold that were not permitted by the state. Over the next 4 months, this search uncovered some 600 water bodies that appeared to be impounded behind unpermitted dams. The DSO then performed inspections of the high hazard projects to verify that they were actually dams, and if so, assessed the condition of the dams and the downstream hazard classification. For those dams that turned out to be high hazard, Notice of Correction letters were sent to the owners requiring them to first make any emergency repairs needed, then to hire an engineer to assess the adequacy of their dams and to design any modifications needed to bring the dams up to current standards. The owners were then given a set amount of time to complete the repairs. Once the repairs were completed, the dams would be considered to be in compliance with state law. 7 pp.